This invention relates to the method and apparatus for quickly and easily placing a uniform and predetermined tension upon a silk-screen mounted to a roller frame for use in the silk-screen process, and more particularly to a system which allows an operator to place the screen material quickly and easily under a prescribed, predetermined uniform tension, and further allows an operator to tension and retension more than one screen at the same station without having to relocate the screen.
Although the silk-screen process is a relatively uncomplex and straightforward process, it is highly competitive, and so therefore it is imperative that the screens be placed on the frame with a predictable uniform tension at a fairly rapid rate and with a minimum of waste of the screen material.
A major breakthrough in terms of reduction of waste and increase of productivity was the invention and utilization of the retensionable roller frame.
Another innovation which directly improves the efficiency of the silk-screening process while reducing the amount of waste was the utilization of precut fabric to incorporate the predicted flexure of the roller frame when placed under tension and the placement of border strips or edges along the precut fabric, such that the strips could simply be snapped into place on the roller frame and then the appropriate tension applied. Often the screen must rest for a period of time between tensioning steps to achieve the appropriate tension without the risk of tearing the fabric.
References known to the inventor which are pertinent to the present invention include:
U.S. Pat. No. 3,601,912 granted to Dubbs, Aug. 31, 1971, which discloses the use of a roller frame for use in the silk-screen process.
U.S. Pat. No. 5,443,003, granted to Larson, Aug. 22, 1995, teaches the use of an improved roller frame in conjunction with a precut fabric, to which an edge has been applied, for quickly snapping into the roller frame.
U.S. Pat. No. 5,488,901, granted to Hruska, Feb. 6, 1996, teaches the use of a hydraulic or pneumatic table for placing a predetermined tension upon a silk-screen stretched upon a roller frame.
U.S. Pat. No. 5,937,753 granted to McKeever, Aug. 17, 1999, teaches another method of utilizing a hydraulic or pneumatic cylinder to place a predetermined amount of tension upon a silk-screen fabric which has been attached to the sides of a roller frame.
With the above noted prior art in mind, it is an object of the present invention to provide a screen tensioning system which, while being of reasonable cost and simple to use, provides a tensioning system which permits a predictable and uniform tension to be placed upon a silk-screen fabric.
It is another object of the present invention to provide a system wherein an operator may quickly and easily attach a screen to a roller frame and then place the appropriate tension thereon.
Still yet another object of the present invention is to provide a silk-screen tensioning system wherein an individual may tension and retension more than one frame at a single station, without needing to remove the previously stretched frame.